/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 26727
 * Date: 2024-05-26
 * Time: 12:27
 */
public class Test7 {
    public static void main(String[] args) {
        String s1 = "hi new classmates";
        String s2 = "HI NEW CLASSMATES";
        //小写转大写
        System.out.println(s1.toUpperCase());
        //大写转小写
        System.out.println(s2.toLowerCase());
    }
}
